There are way too many variables to give you an educated guess as to range without knowing things like how much money you want to spend, what sort of performance parameters you want to see, your minimum required range, your local climate and driving conditions, etc. To get the most out of this forum you need to do some research yourself and learn the lingo and tradeoffs involved in building an EV.
To try and answer your question, Long story short if you were willing to throw a lot of money at it, there is no reason why you could not build a volvo S80 that could do 100 miles (160km) on a charge at freeway speeds. Depending on the size of the trunk you may not even need to sacrifice seating space. The parts are all available off the shelf. But if you are only hoping to spend a couple of thousand dollars to achieve this, forget it. Such a setup would probably cost around $30K (US retail prices for the parts only)